Revert "[clang][UBSan] Add implicit conversion check for bitfields" #87518
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@llvm/pr-subscribers-clang @llvm/pr-subscribers-compiler-rt-sanitizer Author: Vitaly Buka (vitalybuka) ChangesReverts llvm/llvm-project#75481 Breaks multiple bots, see #75481 Patch is 43.31 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/87518.diff 11 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 096376af17acbb..3237842fa1ceb1 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -195,10 +195,6 @@ Non-comprehensive list of changes in this release
New Compiler Flags
------------------
-- ``-fsanitize=implicit-bitfield-conversion`` checks implicit truncation and
- sign change.
-- ``-fsanitize=implicit-integer-conversion`` a group that replaces the previous
- group ``-fsanitize=implicit-conversion``.
- ``-Wmissing-designated-field-initializers``, grouped under ``-Wmissing-field-initializers``.
This diagnostic can be disabled to make ``-Wmissing-field-initializers`` behave
@@ -212,9 +208,6 @@ Modified Compiler Flags
- Added a new diagnostic flag ``-Wreturn-mismatch`` which is grouped under
``-Wreturn-type``, and moved some of the diagnostics previously controlled by
``-Wreturn-type`` under this new flag. Fixes #GH72116.
-- ``-fsanitize=implicit-conversion`` is now a group for both
- ``-fsanitize=implicit-integer-conversion`` and
- ``-fsanitize=implicit-bitfield-conversion``.
- Added ``-Wcast-function-type-mismatch`` under the ``-Wcast-function-type``
warning group. Moved the diagnostic previously controlled by
diff --git a/clang/docs/UndefinedBehaviorSanitizer.rst b/clang/docs/UndefinedBehaviorSanitizer.rst
index 531d56e313826c..8f58c92bd2a163 100644
--- a/clang/docs/UndefinedBehaviorSanitizer.rst
+++ b/clang/docs/UndefinedBehaviorSanitizer.rst
@@ -148,11 +148,6 @@ Available checks are:
Issues caught by this sanitizer are not undefined behavior,
but are often unintentional.
- ``-fsanitize=integer-divide-by-zero``: Integer division by zero.
- - ``-fsanitize=implicit-bitfield-conversion``: Implicit conversion from
- integer of larger bit width to smaller bitfield, if that results in data
- loss. This includes unsigned/signed truncations and sign changes, similarly
- to how the ``-fsanitize=implicit-integer-conversion`` group works, but
- explicitly for bitfields.
- ``-fsanitize=nonnull-attribute``: Passing null pointer as a function
parameter which is declared to never be null.
- ``-fsanitize=null``: Use of a null pointer or creation of a null
@@ -198,8 +193,8 @@ Available checks are:
signed division overflow (``INT_MIN/-1``). Note that checks are still
added even when ``-fwrapv`` is enabled. This sanitizer does not check for
lossy implicit conversions performed before the computation (see
- ``-fsanitize=implicit-integer-conversion``). Both of these two issues are handled
- by ``-fsanitize=implicit-integer-conversion`` group of checks.
+ ``-fsanitize=implicit-conversion``). Both of these two issues are handled
+ by ``-fsanitize=implicit-conversion`` group of checks.
- ``-fsanitize=unreachable``: If control flow reaches an unreachable
program point.
- ``-fsanitize=unsigned-integer-overflow``: Unsigned integer overflow, where
@@ -207,7 +202,7 @@ Available checks are:
type. Unlike signed integer overflow, this is not undefined behavior, but
it is often unintentional. This sanitizer does not check for lossy implicit
conversions performed before such a computation
- (see ``-fsanitize=implicit-integer-conversion``).
+ (see ``-fsanitize=implicit-conversion``).
- ``-fsanitize=vla-bound``: A variable-length array whose bound
does not evaluate to a positive value.
- ``-fsanitize=vptr``: Use of an object whose vptr indicates that it is of
@@ -229,15 +224,11 @@ You can also use the following check groups:
- ``-fsanitize=implicit-integer-arithmetic-value-change``: Catches implicit
conversions that change the arithmetic value of the integer. Enables
``implicit-signed-integer-truncation`` and ``implicit-integer-sign-change``.
- - ``-fsanitize=implicit-integer-conversion``: Checks for suspicious
- behavior of implicit integer conversions. Enables
+ - ``-fsanitize=implicit-conversion``: Checks for suspicious
+ behavior of implicit conversions. Enables
``implicit-unsigned-integer-truncation``,
``implicit-signed-integer-truncation``, and
``implicit-integer-sign-change``.
- - ``-fsanitize=implicit-conversion``: Checks for suspicious
- behavior of implicit conversions. Enables
- ``implicit-integer-conversion``, and
- ``implicit-bitfield-conversion``.
- ``-fsanitize=integer``: Checks for undefined or suspicious integer
behavior (e.g. unsigned integer overflow).
Enables ``signed-integer-overflow``, ``unsigned-integer-overflow``,
diff --git a/clang/include/clang/Basic/Sanitizers.def b/clang/include/clang/Basic/Sanitizers.def
index b228ffd07ee745..c2137e3f61f645 100644
--- a/clang/include/clang/Basic/Sanitizers.def
+++ b/clang/include/clang/Basic/Sanitizers.def
@@ -163,24 +163,24 @@ SANITIZER_GROUP("implicit-integer-arithmetic-value-change",
ImplicitIntegerArithmeticValueChange,
ImplicitIntegerSignChange | ImplicitSignedIntegerTruncation)
-SANITIZER_GROUP("implicit-integer-conversion", ImplicitIntegerConversion,
- ImplicitIntegerArithmeticValueChange |
- ImplicitUnsignedIntegerTruncation)
+SANITIZER("objc-cast", ObjCCast)
-// Implicit bitfield sanitizers
-SANITIZER("implicit-bitfield-conversion", ImplicitBitfieldConversion)
+// FIXME:
+//SANITIZER_GROUP("implicit-integer-conversion", ImplicitIntegerConversion,
+// ImplicitIntegerArithmeticValueChange |
+// ImplicitUnsignedIntegerTruncation)
+//SANITIZER_GROUP("implicit-conversion", ImplicitConversion,
+// ImplicitIntegerConversion)
SANITIZER_GROUP("implicit-conversion", ImplicitConversion,
- ImplicitIntegerConversion |
- ImplicitBitfieldConversion)
+ ImplicitIntegerArithmeticValueChange |
+ ImplicitUnsignedIntegerTruncation)
SANITIZER_GROUP("integer", Integer,
- ImplicitIntegerConversion | IntegerDivideByZero | Shift |
+ ImplicitConversion | IntegerDivideByZero | Shift |
SignedIntegerOverflow | UnsignedIntegerOverflow |
UnsignedShiftBase)
-SANITIZER("objc-cast", ObjCCast)
-
SANITIZER("local-bounds", LocalBounds)
SANITIZER_GROUP("bounds", Bounds, ArrayBounds | LocalBounds)
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index f70324d11a7562..54432353e7420d 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -5580,44 +5580,11 @@ LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
break;
}
- // TODO: Can we de-duplicate this code with the corresponding code in
- // CGExprScalar, similar to the way EmitCompoundAssignmentLValue works?
- RValue RV;
- llvm::Value *Previous = nullptr;
- QualType SrcType = E->getRHS()->getType();
- // Check if LHS is a bitfield, if RHS contains an implicit cast expression
- // we want to extract that value and potentially (if the bitfield sanitizer
- // is enabled) use it to check for an implicit conversion.
- if (E->getLHS()->refersToBitField()) {
- llvm::Value *RHS =
- EmitWithOriginalRHSBitfieldAssignment(E, Previous, &SrcType);
- RV = RValue::get(RHS);
- } else
- RV = EmitAnyExpr(E->getRHS());
-
+ RValue RV = EmitAnyExpr(E->getRHS());
LValue LV = EmitCheckedLValue(E->getLHS(), TCK_Store);
-
if (RV.isScalar())
EmitNullabilityCheck(LV, RV.getScalarVal(), E->getExprLoc());
-
- if (LV.isBitField()) {
- llvm::Value *Result;
- // If bitfield sanitizers are enabled we want to use the result
- // to check whether a truncation or sign change has occurred.
- if (SanOpts.has(SanitizerKind::ImplicitBitfieldConversion))
- EmitStoreThroughBitfieldLValue(RV, LV, &Result);
- else
- EmitStoreThroughBitfieldLValue(RV, LV);
-
- // If the expression contained an implicit conversion, make sure
- // to use the value before the scalar conversion.
- llvm::Value *Src = Previous ? Previous : RV.getScalarVal();
- QualType DstType = E->getLHS()->getType();
- EmitBitfieldConversionCheck(Src, SrcType, Result, DstType,
- LV.getBitFieldInfo(), E->getExprLoc());
- } else
- EmitStoreThroughLValue(RV, LV);
-
+ EmitStoreThroughLValue(RV, LV);
if (getLangOpts().OpenMP)
CGM.getOpenMPRuntime().checkAndEmitLastprivateConditional(*this,
E->getLHS());
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index a4ab8a11b867fa..397b4977acc3e9 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -15,7 +15,6 @@
#include "CGDebugInfo.h"
#include "CGObjCRuntime.h"
#include "CGOpenMPRuntime.h"
-#include "CGRecordLayout.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "ConstantEmitter.h"
@@ -309,7 +308,6 @@ class ScalarExprEmitter
llvm::Type *DstTy, SourceLocation Loc);
/// Known implicit conversion check kinds.
- /// This is used for bitfield conversion checks as well.
/// Keep in sync with the enum of the same name in ubsan_handlers.h
enum ImplicitConversionCheckKind : unsigned char {
ICCK_IntegerTruncation = 0, // Legacy, was only used by clang 7.
@@ -1105,21 +1103,6 @@ void ScalarExprEmitter::EmitIntegerTruncationCheck(Value *Src, QualType SrcType,
{Src, Dst});
}
-static llvm::Value *EmitIsNegativeTestHelper(Value *V, QualType VType,
- const char *Name,
- CGBuilderTy &Builder) {
- bool VSigned = VType->isSignedIntegerOrEnumerationType();
- llvm::Type *VTy = V->getType();
- if (!VSigned) {
- // If the value is unsigned, then it is never negative.
- return llvm::ConstantInt::getFalse(VTy->getContext());
- }
- llvm::Constant *Zero = llvm::ConstantInt::get(VTy, 0);
- return Builder.CreateICmp(llvm::ICmpInst::ICMP_SLT, V, Zero,
- llvm::Twine(Name) + "." + V->getName() +
- ".negativitycheck");
-}
-
// Should be called within CodeGenFunction::SanitizerScope RAII scope.
// Returns 'i1 false' when the conversion Src -> Dst changed the sign.
static std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
@@ -1144,12 +1127,30 @@ EmitIntegerSignChangeCheckHelper(Value *Src, QualType SrcType, Value *Dst,
assert(((SrcBits != DstBits) || (SrcSigned != DstSigned)) &&
"either the widths should be different, or the signednesses.");
+ // NOTE: zero value is considered to be non-negative.
+ auto EmitIsNegativeTest = [&Builder](Value *V, QualType VType,
+ const char *Name) -> Value * {
+ // Is this value a signed type?
+ bool VSigned = VType->isSignedIntegerOrEnumerationType();
+ llvm::Type *VTy = V->getType();
+ if (!VSigned) {
+ // If the value is unsigned, then it is never negative.
+ // FIXME: can we encounter non-scalar VTy here?
+ return llvm::ConstantInt::getFalse(VTy->getContext());
+ }
+ // Get the zero of the same type with which we will be comparing.
+ llvm::Constant *Zero = llvm::ConstantInt::get(VTy, 0);
+ // %V.isnegative = icmp slt %V, 0
+ // I.e is %V *strictly* less than zero, does it have negative value?
+ return Builder.CreateICmp(llvm::ICmpInst::ICMP_SLT, V, Zero,
+ llvm::Twine(Name) + "." + V->getName() +
+ ".negativitycheck");
+ };
+
// 1. Was the old Value negative?
- llvm::Value *SrcIsNegative =
- EmitIsNegativeTestHelper(Src, SrcType, "src", Builder);
+ llvm::Value *SrcIsNegative = EmitIsNegativeTest(Src, SrcType, "src");
// 2. Is the new Value negative?
- llvm::Value *DstIsNegative =
- EmitIsNegativeTestHelper(Dst, DstType, "dst", Builder);
+ llvm::Value *DstIsNegative = EmitIsNegativeTest(Dst, DstType, "dst");
// 3. Now, was the 'negativity status' preserved during the conversion?
// NOTE: conversion from negative to zero is considered to change the sign.
// (We want to get 'false' when the conversion changed the sign)
@@ -1244,136 +1245,6 @@ void ScalarExprEmitter::EmitIntegerSignChangeCheck(Value *Src, QualType SrcType,
{Src, Dst});
}
-// Should be called within CodeGenFunction::SanitizerScope RAII scope.
-// Returns 'i1 false' when the truncation Src -> Dst was lossy.
-static std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
- std::pair<llvm::Value *, SanitizerMask>>
-EmitBitfieldTruncationCheckHelper(Value *Src, QualType SrcType, Value *Dst,
- QualType DstType, CGBuilderTy &Builder) {
- bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType();
- bool DstSigned = DstType->isSignedIntegerOrEnumerationType();
-
- ScalarExprEmitter::ImplicitConversionCheckKind Kind;
- if (!SrcSigned && !DstSigned)
- Kind = ScalarExprEmitter::ICCK_UnsignedIntegerTruncation;
- else
- Kind = ScalarExprEmitter::ICCK_SignedIntegerTruncation;
-
- llvm::Value *Check = nullptr;
- // 1. Extend the truncated value back to the same width as the Src.
- Check = Builder.CreateIntCast(Dst, Src->getType(), DstSigned, "bf.anyext");
- // 2. Equality-compare with the original source value
- Check = Builder.CreateICmpEQ(Check, Src, "bf.truncheck");
- // If the comparison result is 'i1 false', then the truncation was lossy.
-
- return std::make_pair(
- Kind, std::make_pair(Check, SanitizerKind::ImplicitBitfieldConversion));
-}
-
-// Should be called within CodeGenFunction::SanitizerScope RAII scope.
-// Returns 'i1 false' when the conversion Src -> Dst changed the sign.
-static std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
- std::pair<llvm::Value *, SanitizerMask>>
-EmitBitfieldSignChangeCheckHelper(Value *Src, QualType SrcType, Value *Dst,
- QualType DstType, CGBuilderTy &Builder) {
- // 1. Was the old Value negative?
- llvm::Value *SrcIsNegative =
- EmitIsNegativeTestHelper(Src, SrcType, "bf.src", Builder);
- // 2. Is the new Value negative?
- llvm::Value *DstIsNegative =
- EmitIsNegativeTestHelper(Dst, DstType, "bf.dst", Builder);
- // 3. Now, was the 'negativity status' preserved during the conversion?
- // NOTE: conversion from negative to zero is considered to change the sign.
- // (We want to get 'false' when the conversion changed the sign)
- // So we should just equality-compare the negativity statuses.
- llvm::Value *Check = nullptr;
- Check =
- Builder.CreateICmpEQ(SrcIsNegative, DstIsNegative, "bf.signchangecheck");
- // If the comparison result is 'false', then the conversion changed the sign.
- return std::make_pair(
- ScalarExprEmitter::ICCK_IntegerSignChange,
- std::make_pair(Check, SanitizerKind::ImplicitBitfieldConversion));
-}
-
-void CodeGenFunction::EmitBitfieldConversionCheck(Value *Src, QualType SrcType,
- Value *Dst, QualType DstType,
- const CGBitFieldInfo &Info,
- SourceLocation Loc) {
-
- if (!SanOpts.has(SanitizerKind::ImplicitBitfieldConversion))
- return;
-
- // We only care about int->int conversions here.
- // We ignore conversions to/from pointer and/or bool.
- if (!PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(SrcType,
- DstType))
- return;
-
- if (DstType->isBooleanType() || SrcType->isBooleanType())
- return;
-
- // This should be truncation of integral types.
- assert(isa<llvm::IntegerType>(Src->getType()) &&
- isa<llvm::IntegerType>(Dst->getType()) && "non-integer llvm type");
-
- // TODO: Calculate src width to avoid emitting code
- // for unecessary cases.
- unsigned SrcBits = ConvertType(SrcType)->getScalarSizeInBits();
- unsigned DstBits = Info.Size;
-
- bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType();
- bool DstSigned = DstType->isSignedIntegerOrEnumerationType();
-
- CodeGenFunction::SanitizerScope SanScope(this);
-
- std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
- std::pair<llvm::Value *, SanitizerMask>>
- Check;
-
- // Truncation
- bool EmitTruncation = DstBits < SrcBits;
- // If Dst is signed and Src unsigned, we want to be more specific
- // about the CheckKind we emit, in this case we want to emit
- // ICCK_SignedIntegerTruncationOrSignChange.
- bool EmitTruncationFromUnsignedToSigned =
- EmitTruncation && DstSigned && !SrcSigned;
- // Sign change
- bool SameTypeSameSize = SrcSigned == DstSigned && SrcBits == DstBits;
- bool BothUnsigned = !SrcSigned && !DstSigned;
- bool LargerSigned = (DstBits > SrcBits) && DstSigned;
- // We can avoid emitting sign change checks in some obvious cases
- // 1. If Src and Dst have the same signedness and size
- // 2. If both are unsigned sign check is unecessary!
- // 3. If Dst is signed and bigger than Src, either
- // sign-extension or zero-extension will make sure
- // the sign remains.
- bool EmitSignChange = !SameTypeSameSize && !BothUnsigned && !LargerSigned;
-
- if (EmitTruncation)
- Check =
- EmitBitfieldTruncationCheckHelper(Src, SrcType, Dst, DstType, Builder);
- else if (EmitSignChange) {
- assert(((SrcBits != DstBits) || (SrcSigned != DstSigned)) &&
- "either the widths should be different, or the signednesses.");
- Check =
- EmitBitfieldSignChangeCheckHelper(Src, SrcType, Dst, DstType, Builder);
- } else
- return;
-
- ScalarExprEmitter::ImplicitConversionCheckKind CheckKind = Check.first;
- if (EmitTruncationFromUnsignedToSigned)
- CheckKind = ScalarExprEmitter::ICCK_SignedIntegerTruncationOrSignChange;
-
- llvm::Constant *StaticArgs[] = {
- EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(SrcType),
- EmitCheckTypeDescriptor(DstType),
- llvm::ConstantInt::get(Builder.getInt8Ty(), CheckKind),
- llvm::ConstantInt::get(Builder.getInt32Ty(), Info.Size)};
-
- EmitCheck(Check.second, SanitizerHandler::ImplicitConversion, StaticArgs,
- {Src, Dst});
-}
-
Value *ScalarExprEmitter::EmitScalarCast(Value *Src, QualType SrcType,
QualType DstType, llvm::Type *SrcTy,
llvm::Type *DstTy,
@@ -2749,8 +2620,6 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
llvm::PHINode *atomicPHI = nullptr;
llvm::Value *value;
llvm::Value *input;
- llvm::Value *Previous = nullptr;
- QualType SrcType = E->getType();
int amount = (isInc ? 1 : -1);
bool isSubtraction = !isInc;
@@ -2839,8 +2708,7 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
"base or promoted) will be signed, or the bitwidths will match.");
}
if (CGF.SanOpts.hasOneOf(
- SanitizerKind::ImplicitIntegerArithmeticValueChange |
- SanitizerKind::ImplicitBitfieldConversion) &&
+ SanitizerKind::ImplicitIntegerArithmeticValueChange) &&
canPerformLossyDemotionCheck) {
// While `x += 1` (for `x` with width less than int) is modeled as
// promotion+arithmetics+demotion, and we can catch lossy demotion with
@@ -2851,26 +2719,13 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
// the increment/decrement in the wider type, and finally
// perform the demotion. This will catch lossy demotions.
- // We have a special case for bitfields defined using all the bits of the
- // type. In this case we need to do the same trick as for the integer
- // sanitizer checks, i.e., promotion -> increment/decrement -> demotion.
-
value = EmitScalarConversion(value, type, promotedType, E->getExprLoc());
Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
// Do pass non-default ScalarConversionOpts so that sanitize...
[truncated]
|
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Apr 3, 2024
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…ields"" (#87529) Reverts #87518 Revert is not needed as the regression was fixed with 1189e87. I assumed the crash and warning are different issues, but according to https://lab.llvm.org/buildbot/#/builders/240/builds/26629 fixing warning resolves the crash.
vitalybuka
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Apr 3, 2024
…for bitfields""" (#87562) Reverts #87529 Reverts #87518 https://lab.llvm.org/buildbot/#/builders/37/builds/33262 is still broken
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Reverts #75481
Breaks multiple bots, see #75481